Submission #87159

#	Time	Username	Problem	Language	Result	Execution time	Memory
87159		fedoseevtimofey	Circle selection (APIO18_circle_selection)	C++14	49 / 100	3038 ms	357156 KiB

circle_selection

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
 
int n;
vector <int> x, y, r;
 
void init() {
    cin >> n;
    x.resize(n);
    y.resize(n);
    r.resize(n);
    for (int i = 0; i < n; ++i) {
        cin >> x[i] >> y[i] >> r[i];
    }
}
 
bool inter(int i, int j) {
    return (ll)(x[i] - x[j]) * (x[i] - x[j]) + (ll)(y[i] - y[j]) * (y[i] - y[j]) <= (ll)(r[i] + r[j]) * (r[i] + r[j]);
}
 
map <pair <int, int>, vector <int>> who;
 
set <int> alive;
 
void rebuild(int B) {
    who.clear();
    for (auto i : alive) {
        int xx = x[i] / B;
        int yy = y[i] / B;
        who[make_pair(xx, yy)].push_back(i);
    }
}
 
void solve() {
    for (int i = 0; i < n; ++i) alive.insert(i);
    vector <int> idx(n);
    iota(idx.begin(), idx.end(), 0);
    sort(idx.begin(), idx.end(), [&] (int i, int j) {
        if (r[i] != r[j]) return r[i] > r[j];
        return i < j;
    });
    vector <int> kill(n, -1);
    int uk = 0;
    for (int B = 1 << 30; B > 0; B >>= 1) {
        bool fl = false;
        while (true) {
            while (uk < n && kill[idx[uk]] != -1) ++uk;
            if (uk == n) break;
            int cur = idx[uk];
            if (!fl) {
                B = r[cur];
                rebuild(B);
                fl = true; 
            }
            else {
                if (B >> 1 >= r[cur]) break;
            }
            alive.erase(cur);
            kill[cur] = cur;
            int xx = x[cur] / B;
            int yy = y[cur] / B;
            for (int cx = xx - 2; cx <= xx + 2; ++cx) {
                for (int cy = yy - 2; cy <= yy + 2; ++cy) {
                    vector <int> nw;
                    for (auto j : who[make_pair(cx, cy)]) {
                        if (kill[j] != -1) continue;
                        if (inter(cur, j)) {
                            kill[j] = cur;
                            alive.erase(j);
                        }
                        else {
                            nw.push_back(j);
                        }
                    }
                    who[make_pair(cx, cy)] = nw;
                }
            }
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << kill[i] + 1 << ' ';
    }
}
 
int main() {
    ios_base::sync_with_stdio(false); cin.tie(0); cout.setf(ios::fixed); cout.precision(20);
    #ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
    init();
    solve();
}

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 30 / 30
• Subtask 6: 0 / 13